Remove hardcoded tokens, opt for environment variable

examples/echo_bot.py

@@ -1,6 +1,7 @@
 import asyncio
 import logging
 import sys
+from os import getenv
 
 from aiogram import Bot, Dispatcher, Router, types
 from aiogram.enums import ParseMode
@@ -9,9 +10,7 @@ from aiogram.types import Message
 from aiogram.utils.markdown import hbold
 
 # Bot token can be obtained via https://t.me/BotFather
-TOKEN = "42:TOKEN"
-# However, is recommended to get the token from environment variable:
-# TOKEN = getenv("BOT_TOKEN")
+TOKEN = getenv("BOT_TOKEN")
 
 # All handlers should be attached to the Router (or Dispatcher)
 router = Router()